1. Field of the Invention
This invention is concerned with the catalytic conversion of hydrocarbons and other organic compounds over crystalline aluminosilicate zeolites of the ZSM-5 type which have been modified by treatment with BF.sub.3, to provide enhanced selectivity, activity, or both, and with the method for preparing such catalysts.
2. Description of the Prior Art
Zeolitic materials, both natural and synthetic, have been demonstrated in the past to have catalytic properties for various types of conversions. One such conversion which has generated considerable interest is the production of hydrocarbons, including olefins and gasoline from alcohols and ethers.
U.S. Pat. No. 4,025,575 describes a process by which lower alcohols and/or their ethers are converted to a mixture of C.sub.2 -C.sub.5 olefins by contact at subatmospheric inlet partial pressure with a crystalline aluminosilicate zeolite of the ZSM-5 type.
U.S. Pat. No. 3,931,349, issued Jan. 9, 1976, also discloses a process for the conversion of methanol to gasoline utilizing a ZMS-5 type catalyst.
U.S. Pat. No. 4,083,888, issued on Apr. 11, 1978, discloses a process for the manufacture of hydrocarbons by the catalytic conversion of methanol in the presence of a substantially anhydrous diluent and a ZSM-5 type zeolite.
There are many other patents and publications which describe the conversion of methanol to hydrocarbons, including gasoline, such as U.S. Pat. No. 3,931,349; 3,969,426; 3,899,544; 3,894,104; 3,904,916; and 3,894,102, the disclosures of which are incorporated herein by reference. Other conversions include, for example, propylene oligomerization, toluene disproportionation, xylene isomerization, alkylation of aromatics with alcohol or olefins, such as toluene+ethylene--p-ethyltoluene, and dewaxing, i.e., shape-selective cracking of wax molecules.
U.S. Pat. No. 4,163,028 discloses the isomerization of a feedstock containing xylene in the presence of ZSM-5. U.S. Pat. No. 4,268,420 describes a crystalline borosilicate AMS-1B (ZSM-5) which can be used as a catalyst in the isomerization of xylene.
U.S. Pat. No. 4,292,457 discloses the alkylation of aromatic hydrocarbons in the presence of a borosilicate AMS-1B (ZSM-5) catalyst. U.S. Pat. No. 4,269,813 discloses the use of this catalyst in disproportionation and transalkylation processes as well as in xylene isomerization. Similar processes in the presence of ZSM-4 and ZSM-5 catalysts are also disclosed in U.S. Pat. No. 4,377,502.
U.S. Pat. No. 4,208,305 and U.S. Pat. No. 4,238,318 disclose, in addition to the above catalytic processes, upgrading cracked gasoline and naphtha, preparation of olefins from alcohols, preparation of olefinic gasoline, alkylation of olefins, separation of hydrogen mixtures, and catalytic hydrodewaxing of hydrocarbon oils in the presence of zeolite catalysts.
All of the foregoing patents are incorporated herein by reference.